Machine for bending sheet metal



Aug. 6, 1968 L. MILLE 3,395,846

MACHINE FOR BENDING SHEET METAL Filed Aug. 8, 1966 2 Sheets-Sheet 1 Aug. 6, 1968 L. MILLE 3,395,846

MACHINE FOR BENDING SHEET METAL Filed Aug. 8, 1966 2 Sheets-Sheet 2 Fig. 5

United States Patent 6 Claims. (cl. 228-) ABSTRACT OF THE DISCLOSURE This disclosure is concerned with a machine for bending sheet metal to form a regular polygonal sleeve in which are provided a primary shaft adapted to be driven in continuous rotation, advancing means kinematically connected to and actuated by the primary shaft during a first portion of the rotation thereof whereby the sheet metal is advanced intermittently by a predetermined constant amount; gripping means connectedto and actuated by the primary shaft during a second portion of the rotation thereof to grip the sheet metal after each advance; and bending means connected to and actuated by the primary shaft at least during part of the second portion of the rotation thereof whereby the bending means bends the gripped sheet metal through a predetermined constant angle.

The present invention concerns a machine for bending sheet metal while permitting the realization of polygonal sleeves of different diameters.

It concerns, more particularly, a machine which, beginning with a plain sheet of metal, forms a prism whose section is a regular polygon having a fixed number of sides, each cord constituting one side or step of the polygon, characterizing a given diameter for the circumscribed circle.

The known classic process which has been used up till now for bending sheet metal, consists in making the sheet metal pass between cylinders taking the sheet metal by its two faces and disposed relatively one with respect to the other in such a way that a cylinder is formed in a continuous way while assuring that each point of the sheet metal be of the same curvature.

An object of the present invention consists in a process for bending for sheet metal continuously, by establishing a regular, convex polygonal line, which is closed by welding the two ends edge to edge. i I

Another object consists in an apparatus for carrying out the process according to the characteristics indicated above.

These objects, as well as other objects and advantages resulting from the means for carrying out the process, will appear clearly to the reader from the following description, given by way of non-limiting example, of a preferred embodiment, made by referring to the accompanying drawings, in which:

FIGURE 1 shows the members for driving, folding, and cutting the sheet metal;

FIGURE 2 shows the control device for the advance and the driving;

FIGURE 3 shows the gear-reducing device;

FIGURES 4a and 4b show the system of support for the mandrel and for the counter blade;

FIGURE 5 shows the mandrel and the welding table for the sleeve.

In FIGURES 1 and 2 have been shown the driving members having a regulable travel and intermittent movement, functioning as follows:

A primary shaft 1 comprises fixed on its axle, a plate- 3,395,846 Patented Aug. 6, 1968 crank 3, carrying an arbor 2 which can occupy a position variable at will along the vertical radius of the plate 3.

A rod 4 is articulated on the movable arbor 2 and connected to another plate 5 by the intermediary of a supple element 6, which can be constituted by a chain or a cable, engaged in the groove of the plate 5.

The other end of the element 6 is fixed to a helical spring 7 assuring constantly a tensioning of the said supple element.

A ratchet device or spring catch 8 is rigid with the plate 5 and co-operates with the kinematic assembly described above to assure the driving of a toothed wheel 9, against which the click 8a comes to abut.

In the course of its rotation, and at an angular value in the neighborhood of the axle 1 drives the toothed wheel 9 with a proportional value. The value of the complementary rotation at 360? assures that the plate 5 and the click device 8 are put in their initial position. In this later phase, which assures a return to the starting conditions, the toothed wheel 9 remains stationary.

The toothed wheel 9 is rigid with a sleeve or hollow shaft 10 carried by the axle 11. The toothed wheel 9, by the intermediary of a reducer, constituted by the pinions a and b contained in the frame 12, drive the cylinder 13 whose axle 11 carries the pinion a keyed on it.

This cylinder 13 moves in synchronism with the cylinder 14, to which it is connected by a gear train (not shown).

The sheet metal 16 is taken between the cylinders 13 and 14 which pinch it under the action of the jack 15 actuating the lower cylinder 14.

During the dead time in the course of which the toothed Wheel 9 is not driven, the kinematic assembly constituted by the pinions d (rigid with the hollow shaft 10) c, b and a (this later being keyed on the axle 11) remain stationary and the sheet metal is not advanced. It is supported by the counter-blade 17 of the fixed jaw of the vice, and locked by a blade 18 of the movable jaw 19 of the vice. The movable jaw 19 is moved in the course of the rotation of the primary shaft 1, by the intermediary of a set of cams 20 and a roller 21, in the course of the dead time of the two advancing cylinders 13 and 14.

Two identical pinions 22a, and 22b, of which the former is rigid with the primary shaft 1, transmit to an axle 23 the movement of the said primary shaft. The axle 23 carries a couple of eccentrics 24 at the ends rigid with two rods 25 carrying fixed to their lower end a folding blade 26 parallel to the fixed and movable jaws 17 and 18.

When the blade 26 is in the lowered position, clearly below the plane of the fixed jaw 17, it folds the supported sheet metal 16 around the exterior edge of the said jaw.

By contrast, in the active phase of the two driving cylinders 13 and 14, the cam 20 on which the wheel 21 rolls, has a profile of lesser thickness, such that the pressure which is exerted by the blade 18 of the movable jaw 19 is annulled under the effect of the compensator spring 30 which urges this latter towards the top, making it pivot around the axle 40.

The folding blade 26, which has been driven by the set of eccentrics 24, is located then in the upper position.

At the same time, the sheet metal is driven by the cylinders 13 and 14 by an amount determined by the length of the arm of the crank, a function of the position of the arbor 2 on the vertical radius.

For one complete revolution of the shaft, it effects successively: I

(a) an advance of the sheet metal by a well-defined length,

(b) a folding of the sheet metal, according to a welldetermined angle,

which is simply a function of the geometry of the arms 25 carrying the knife.

To fashion the sleeve, the assembly of phase constituting this cycle is repeated a fixed number of times, at a rhythm which can be for example sixty blows per minute, which would permit a sixty-sided sleeve to be obtained in one minute, each cycle lasting only one second.

For each revolution, a contactor 41 (FIGURE 2) permits the end of the cycle to be detected and transmits to a counter an impulse at each revolution of the primary shaft.

A warning system can be provided to interrupt the advance after sixty blows, permitting to pass to the following stage of the operations, which is the phase of shearing.

The movement of the primary shaft can then be locked under the effect of an electromagnetic brake-clutching system, in the position in which the jaws 17 and 18 are closed on the sheet metal 16.

The folding blade 26 is stabilised before its contact with the sheet metal 16. Synchronized with the stopping of the primary shaft, the movement of a couple of eccentrics 29 pushes rods 25 away by the intermediary of arms 28 which pivot at 27 on the said rods, thus moving the blade away from the folding jaw 17.

This latter in the course of its backwards movement touches a contactor 40 which clutches the control shaft 32 of the knife of the shears 36, to which it is connected by the intermediary of an eccentric 33, a rod 34 which is articulated at 35 with the body of the tool 36. In the course of the rotation of the eccentric 33, the shearing blade 36 effects a vertical movement, descending then ascending, of which the end of the first phase is achieved by the sectioning of the sheet metal. at the level of the external flank of the counter blade 17 of the fixed jaw of the vice, according to a generatrix of the cylinder thus formed.

When the volution of the shaft 32 is complete, the blade is brought up again to the upper position and the eccentric closes the contactor 42 which transmits an impulse on the electro-gate of a jack (not shown), which brings back the folding knife 26 to its work position and actuates then the jack 43 shown in FIGURE 5, which drives the sleeve 44 off the mandrel 39, supported by some rollers 37 and 38, whose height with respect to the mandrel is regulated as a function of the diameter of the sleeve, towards the welding post 47.

The counter blade 17 is rigid with the mandrel 39 in which it is fitted, the assembly being supported from place to place on the frame 45 by some brackets 46 anchored at the same time to the frame and to the ends 4 of the mandrel, as shown in FIGURES 4a and 4b. Although the present description has been made with reference to an embodiment preferred by the inventor, various modifications of form and/ or of detail can be made without departing from the spirit of the invention.

What is claimed is:

1. Machine for bending sheet metal to form a regular polygonal sleeve comprising:

(i) a primary shaft adapted to be driven in continuous rotation,

(ii) advancing means kinematically connected to and actuated by the primary shaft during a first portion of the rotation of the primary shaft whereby the advancing means advances the sheet metal intermittently by a predetermined, constant amount,

(iii) gripping means connected to and actuated by the primary shaft during a second portion of the rotation of the primary shaft whereby the gripping means grips the sheet metal after each advance,

, (iv) and bending means connected to and actuated by the primary shaft at least during part of the second portion of the rotation of the primary shaft whereby the bending means bends the gripped sheet metal through a predetermined constant angle.

2. Machine according to claim 1 including shearing means for shearing the sheet metal after the completion of a number of bends suflicient to close the polygonal sleeve.

3. Machine according to claim 2 including a counter adapted to count the number of bends, and further adapted to actuate the shearing means to shear the sheet metal after said sufficient number of bends.

4. Machine according to claim 2 in which said gripping means comprises a pair of jaws, and said bending means co-operates with one of the jaws to bend the sheet metal around said one jaw.

5. Machine according to claim 4 in which said shearing means co-operates with said one jaw to shear the sheet metal.

6. Machine according to claim 2 including supporting means for supporting the sheared-off portion of the sheet metal, a welding post remote from the bending means at which the two ends of the sheared-off portion can be welded together to complete the sleeve, and a jack to push the sheared-off portion from the vicinity of the bending means to the welding post.

References Cited UNITED STATES PATENTS RICHARD H. EANES, J R., Primary Examiner. 

